An eye diagram is a valuable tool in the study of serial data communication systems. The diagram is formed by overlapping sampled signal waveforms over a specified time interval. An eye diagram provides a qualitative means to evaluate link performance and to troubleshoot system issues. Careful analysis of this visual display can offer insights into channel impairments such as inter-symbol interference (ISI) and yield a first order approximation of signal-to-noise and clock timing jitter.
The eye diagram has been offered as an indispensable feature for most oscilloscope vendors such as Agilent (Santa Clara, Calif.), Tektronix (Beaverton, Oreg.), and Synthesis Research Inc (Menlo Park, Calif.). Many physical layer integrated circuit (IC) providers are also beginning to include an on-chip eye capture and display feature as a part of serializer and deserializer (SerDes) product offering.